macos - 如何使用 AUMatrixMixer

Question

我知道 AUMatrixMixer 是我需要的。 “将任意数量的输入混合为任意数量的输出的单元。”

我在这里找到了一些信息: http://coreaudio-audiounits.blogspot.ca/2013/04/aumatrixmixer-simplified.html http://developer.apple.com/library/ios/#documentation/AudioUnit/Reference/AudioUnitPropertiesReference/Reference/reference.html

但是关于如何实现它的文档是不存在的。我将如何设置它，我将如何将特定输入路由到混音器到特定输出；即如何设置矩阵。

Answer 1

coreaudio-api 列表上有一篇帖子可能会有所帮助 ( http://lists.apple.com/archives/coreaudio-api/2008/Apr/msg00169.html ):

The matrix mixer allows you to connect any number of input and ouput elements with any number of channels each. You need to make sure you set the stream formats of the inputs and outputs so that the channel numbers are correct. Each input and output channel is numbered sequentially across all elements. So if you were to connect one stereo inputs, one mono input, and another stereo input, the channels in the mixer would be numbered as follows: stereo: 0 1 mono: 2 stereo: 3 4 Outputs are numbered in a similar fashion.

The channel numbers are what you use to set gains in the matrix. The matrix has 4 gain controls that can affect any particular route from input to output:

master gain (global scope) - affects the gain of all outputs

input channel gain (input scope) - affects the gain of a particular input channel

output channel gain (output scope) - affects the gain of a particular output channel

crosspoint gain (global scope) - controls the gain of a single input channel going to a single output channel. You make connections from inputs to outputs by setting crosspoint gains to nonzero values.

When setting crosspoint gain parameters, the element number is used differently from other audio units. Crosspoints are set using an element number that is constructed from both the input and the output channel numbers as follows:

element_number = (input_channel << 16) | output_channel

Master gain has element number 0xFFFFFFFF.